LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Davide Libenzi <davidel@xmailserver.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch] epoll reduced (to 1) number of passes over the ready set ...
Date: Wed, 28 Feb 2007 07:29:03 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0702280727590.5935@alien.or.mcafeemobile.com> (raw)
In-Reply-To: <200702281213.59695.dada1@cosmosbay.com>

On Wed, 28 Feb 2007, Eric Dumazet wrote:

> On Tuesday 27 February 2007 17:03, Davide Libenzi wrote:
> > On Tue, 27 Feb 2007, Eric Dumazet wrote:
> > > On Tuesday 27 February 2007 03:32, Davide Libenzi wrote:
> > > > Epoll is doing multiple passes over the ready set at the moment,
> > > > because of the constraints over the f_op->poll() call. Looking at the
> > > > code again, I noticed that we already hold the epoll semaphore in read,
> > > > and this (together with other locking conditions that hold while doing
> > > > an epoll_wait()) can lead to a smarter way to "ship" events to
> > > > userspace (in a single pass). I added more (even) more comments to the
> > > > code to explain the conditions why certain operations are safe.
> > > > This is a stress application that can be used to test the new code. It
> > > > spwans multiple thread and call epoll_wait() and epoll_ctl() from many
> > > > threads. Stress tested on my dual Opteron 254 w/out any problems.
> > >
> > > Davide,
> > >
> > > This is really cool, because the size of epitem would fit now in 128
> > > bytes instead of 192 (on x86_64 platforms). So we also reduce memory
> > > usage.
> >
> > Yeah, I forgot to mention that I removed the txlink member.
> 
> I am pretty sure you can also remove revents member from epitem.
> 
> It would greatly benefit to 32bits platforms, because resulting size would be 
> 64 bytes instead of 68 (so a 50 % reduction because of 64 bytes alignment)

Yes indee. That does not need to exist anymore, once the de-coupled loop 
is gone. Thx, I'll make a new patch later today.


- Davide



      reply	other threads:[~2007-02-28 15:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-27  2:32 Davide Libenzi
2007-02-27  4:00 ` Linus Torvalds
2007-02-27  4:14   ` Davide Libenzi
2007-02-27  9:15 ` Eric Dumazet
2007-02-27 16:03   ` Davide Libenzi
2007-02-28 11:13     ` Eric Dumazet
2007-02-28 15:29       ` Davide Libenzi [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Pine.LNX.4.64.0702280727590.5935@alien.or.mcafeemobile.com \
    --to=davidel@xmailserver.org \
    --cc=akpm@linux-foundation.org \
    --cc=dada1@cosmosbay.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [patch] epoll reduced (to 1) number of passes over the ready set ...' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).